Any Advice on MIG Welding an '88 Peterbilt Frame for a Beginner Welder?

I guess I’m a little confused at why you need to weld anything. Seems like you need to just cut it down.

 

I always agreed welding with rod, but seems quite a few here have done it with wire.

OP, whack that frame off with a torch. Cut into pieces, and you've got lots of practice welding there.

And as @ElmerFudpucker said, why will you need to weld anything?

 

You got wheelbase to add. Move the axles back. Put the front spring hanger in the rear hanger position. Punch new holes for the rear hanger and fifth wheel mount. Cut and trim flange at rear of frame to get the taper you want and make a mudflap hanger point there. Mig welding that spot will be perfectly fine.

 

I don't know a ton about frames but in my brief time in a fab shop pretty much everything was done with wire. As to what wire to use on a truck frame I wouldn't have the faintest idea.

We were burning together up to 1" material with 1/16" flux core and gas. Welds came out beautiful, the slag would come off with a blow gun if it didn't fall off on its own.

 

When you consider that everything automotive is welded with wire and has been for 50 years. Aluminum and steel both. Wire works.

 

This. You have so much going on to make sure it’s straight and lined up you don’t want the pressure on you to weld it as well. And I could be wrong but if you get in an accident and a Lawyer finds out you manufactured that frame and it was the cause of the accident you are toast. Put this responsibility on someone else.

 

This guy has lots of info on working on frame rails

https://youtube.com/shorts/bdScEz1TITw?si=T3k8GPqBveUz1HAP